1. Field of the Invention
The present invention relates to a machine for marking hollow parts and a method for marking hollow parts and for controlling the quality of their marking.
Within the meaning of the invention, a hollow part is a part that is at least partly tubular with a noncircular cross section.
2. Description of the Related Art
To mark hollow parts, it is a known practice to use a marking machine comprising a marking member, such as a flat stamp or a screen-printing doctor blade, and at least one mandrel for supporting the parts for them to be marked by this marking member. Furthermore, FR-A-2 633 062 discloses, in the case of parts with a circular cross section, the practice of integrating into a marking machine a device for controlling the quality of the marking of the parts. More specifically, this document divulges a screen-printing marking machine comprising two distinct stations, designed respectively for marking and quality control. In these two stations, the part to be marked or to be controlled is rotated about its central axis. The marking is made by moving a print screen relative to the surface of the part to be marked. The quality of the marking is controlled by moving a camera relative to the marked surface of the part to be controlled, so that the camera reads each marking line of the part. In the case of parts of circular cross section, the movement to be communicated to the camera is relatively simple. However, this movement rapidly becomes complex in the case of parts whose marked surface has variations of curvature radius.
It is this disadvantage that the invention aims more particularly to remedy by proposing a machine for marking hollow parts making it possible to effectively control the quality of the marking of the parts, with the aid of a camera whose movement relative to the marked surface of the parts is simple, irrespective of the profile of the parts.